Document disintegrating method



4 Sheets-Sheet l NNN I. ILL

July 6, 1965 J. E. OCONNOR nocumnuw DISINTEGRATING mmnon Original FiledApril 5, 1963 July 6, 1965 J. E. O'CONNOR 3,192,853

, DOCUMENT DISINTEGRATING METHOD Original Filed April 5, 1963 4Sheets-Sheet 2 F" 1 if y 6, 1965 I. E. O'CONNOR 3,192,853

I DOCUMENT DISINTEGRATING METHOD Original Filed April 5, 1963 4Sheets-Sheet 3 206 209 0 \O Q I, II 24! Q Q i 212 214 M/1 6/V 70A 214J2me: 6 OJwmer July 6, 1965 J. E. OCONNOR vocumnn'r DISINTEGRATINGMETHOD Original Filed April 5, 1965 4 Sheets-Sheet 4 United StatesPatent 'Original application Apr. 5, 1963, Ser. No. 285,162.

Divided and this application Nov. 27, 1964, Ser. No. 414,328 5 Claims.(Cl. 10039) This application is a division of copending applicationSerial No. 285,162, filed April 5, 1963, entitled DocumentDisintegrating Mechanism.

The present invention relates to disposal methods, and it relates moreparticularly to an improved method for destroying, disintegrating anddisposing of classified documents and similar material, after thematerial has served its intended purpose.

It is usual in the United States, and in other countries, to classifyall documents, books, reports, proposals, drawings, or other materialafiecting the defense of the country. This material has several degreesof classification ranging, for example, from confidentia to top secret.

The destruction of classified material once it has served its purposehas long presented a serious security problem. It is evident that, ineach instance, every precaution must be made to assure that theparticular document to be destroyed is, in fact, destroyed, and that thedocument does not fall into the hands of unauthorized persons. It isalso evident that practical economics presents a serious factor inproviding adequate supervision by security oflicers, especially wherelarge quantities of classified material are to be destroyed on a dailybasis, as is the case in many of the larger defense facilities and inthe plants of the larger firms with extensive government contracts.

A usual procedure in the past has been to burn the classified materialto be destroyed. This has involved, however, elaborate systems forgathering the material, taking the material to a central burning point,and supervising the burning of the material.

The operations involved in providing for the routine burning ofclassified material have proven to be most expensive in that theyrequire a relatively large number of security ofiicers for relativelylong periods of time. Also, ditliculties have been encountered inproviding suitable central burning plants which are capable ofadequately performing their intended function without creating a smokenuisance in the surrounding neighborhood.

Because of the difficulties encountered in burning classified materialwhich is to be destroyed, the Department of Defense has recentlyauthorized other procedures for the destruction of classified documents.These latter procedures involve either pulping the material, or millingthe material by hammer mill mechanisms. 7

The pulping procedures have -proven to be relatively slow andcumbersome. These procedures involve feeding the classified papers intoa large vat and mixing them 3 with water until they are formed into anundistinguishable pulp. As noted, the pulping procedures are relativelyslow, and require close and lengthy supervision to assure that all thepapers fed into the pulping vat are fully and completely destroyed.

The milling procedure appears to be the most feasible. However, thisprocedure also in the past has created problems in that complicatedsecurity measures were previously considered necessary to supervise thefeeding of the papers into the milling mechanism, and of assuring thatthe papers are fully and completely destroyed in the mechanism.

An object of the present invention is to provide a method for destroyingand disposing of classified material by mechanical means, which methodoperates on a closed ice system principle so as to require a minimum ofsecurity supervision, and by which the violation of security or theunauthorized removal of the documents from the mechanism is positivelyprevented. 7

Another object is to provide such an improved method which absolutelyassures that all documents will be completely destroyed.

In the practice of the invention, as exemplified in the embodiment to bedescribed, the disposal apparatus is mounted on a trailer truck to betransported, for example, from plant to plant, and from point to pointwithin a plant.

The apparatus is constructed to receive, for example, locked wheeledbins which have slots to receive the classified material at originatinglocations. These bins are normally positioned at diiferent points in theparticular plant, and are chain locked, for example, to appropriateposts, or the like, at these areas to prevent their unauthorized removal.

When the bins are so positioned around the plant, all classifieddocuments to be destroyed may be deposited in them through appropriateslots. The mobile unit incorporating the apparatus to be described thenmakes scheduled visits to the plant. Prior to such a scheduled visit, asecurity officer removes all the bins from their normal points andwheels them, still locked, to a chosen area. This chosen area, forexample, may be just within the gates of the plant, so that the gateguard may be charged with the duty of supervising the destruction of theclassified documents. It will be appreciated as the present descriptionproceeds, that a single security oflicer is capable of wheeling all thelocked bins to the chosen area, and the intermittent attention only ofthe gate guard is required in the actual destruction of the material.

Upon the arrival of the mobile unit incorporating the the apparatus. Thegate guard then unlocks the cover of the particular bin, withoutremoving the bin from its enclosed locked feeding position. Afterunlocking the cover of the bin, the gate guard can return to his normalduties. When the cover of the bin is unlocked, it opens and the materialin the bin flows down a closed conduit in the apparatus to be completelydestroyed. When the destruction process is completed, the gate guardreturns to unlock the empty bin from the apparatus, and to supervise themovement of a second locked bin into position on the apparatus, in themanner described above.

As will become more evident as the description proceeds, the entiredestruction of the classified material of a large plant may be carriedout under the supervision of a first security officer Whose dutiesinvolve moving the bins to the chosen area, and under the intermittentsupervision of the gate guard whose duty involves unlocking.

the bins on the apparatus, and subsequently unlocking the unloaded binsfrom the apparatus.

An important feature of the process of the present invention, therefore,is the saving in time and numbers of security officers. This saving isrealized by the fact that once a document is inserted into one of thebins referred to above, the document follows a path to its ultimatedestruction which is completely enclosed and which is not susceptible tosecurity violation.

Other features and advantages of the invention will become apparent froma consideration of the following specification in conjunction with theaccompanying drawings, in which:

FIGURE 1 shows a mobile unit incorporating apparatus for practicing oneembodiment of the method of the invention;

' FIGURE 2 is a fragmentary sectional view, substantially on the line2-2 of FIGURE 1, and showing the .2 details of a helical outlet feedingmechanism included in the apparatus;

FIGURE 3 is a fragmentary perspective 'view of the apparatus of FIGURE1, taken from the rear of the view of FIGURE 1 and showing a portion ofthe apparatus on a reduced scale;

FIGURE 4 is an end elevational view of the apparatus of FIGURE 1, butwith one of the components of the apparatus of FIGURE I removed, forpurposes of clarity;

FIGURE 5 is a fragmentary view showing the manner in which a bincontaining classified material is held in place on top of the apparatus,so that its material may be fed into the apparatus to be destroyed;

FIGURE 6 is a fragmentary sectional view showing the details of themilling component of the apparatus;

FIGURE 7 is also a fragmentary sectional view, showing the manner inwhich the material isfed through a closed conduit and conveyor to themilling component of the apparatus;

FIGURE 8 is a top perspective view of a bin containing classifiedmaterial, the bin being illustrated in its locked position, and ready tobe elevated to the top of the apparatus of the invention;

FIGURE 9 is a fragmentary sectional view of a modified apparatus forpracticing a further embodiment of the process of the invention; and

FIGURE 10 is a perspective view of other components of the modifiedapparatus of FIGURE 9.

As illustrated in FIGURE 1, for example, the apparatus disclosed hereinis mounted on a trailer truck 10. The trailer truck has an additionaltrailer 12 coupled to it, and the trailer 12 supports a diesel, or othertype of engine, 14 of usual construction.

The apparatus includes a milling mechanism 16 which is mounted on a pairof I-beams 18 and 20 on the bed of the trailer truck 13. The millingmechanism 16 may be a hammer mill of the type, for example, presentlymanufactured by the Williams Patent Crusher and Pulverizer Co., Inc. ofSt. Louis, Missouri.

The milling mechanism includes a rotor 29 which is mounted on a centralshaft 22. The central shaft'22 is suitably journaled, and it is drivenby the drive shaft 24 of the diesel engine 14. The shaft 24 is coupledto the shaft 22 by suitable couplings 26, as illustrated in FIG- URE 1.

The milling mechanism includes a conduit 28 which defines an inlet forthe mechanism, through which the material to be destroyed is fed. Themechanism also includes a conduit 34) which defines the outlet from themilling mechanism, and through which the material from the mechanism isfed. A grate 32 (FIGURE 6) is positioned at the entrance of the outlet.This grate has an arcuate configuration, as shown in FIGURE 6, and it isformed of a series of parallel grate bars which are positioned to definepredetermined openings between each adjacent bar.

The rotor 20 of the milling mechanism includes a plurality of hammers,or Crushers, 34. These hammers are pivotally mounted on the rotor 20 bymeans of corre- The drive shaft 22 also drives a fan 50 (FIGURE 1).

The fan 50 may be of any suitable construction, and it is mounted at oneend of the milling mechanism 16. The fan serves to draw air in throughan inlet formed by a conduit 52 and past the outlet formed by theconduit 30 (FIGURE 7) to an outlet tube 54. The fan serves to draw thematerial through the conduit 36 from the milling mechanism 16 and tofeed the material into a tank 4 56. The tank 56 is mounted on theforward end of the bed of the truck 16, as illustrated in FIGURE. 1.

The lower end of the tank 56 is coupled to an outlet tube 58 which, inturn, is integral with a tubular conveyor housing 6%). The conveyorhousing 59 extends across the bed of the truck 10, and it, including atelescopic sleeve-like portion 62a, can be moved to an extendedposition, as shown by the broken lines in FIGURE 1. A helical conveyor62 is mounted in the housing 60, as shown in FIGURE 2. The conveyor 62is driven by the drive shaft 22 through a suitable coupling, not shown.As shown in FIGURE 2, the helical conveyor 62 is tapered, and thisconveyor serves to compress the fluffy material from the tank 56, and toforce the compressed material out through the end of the extended tube6%. The resulting material may be loaded into any appropriate vehicle,such as the cart 64. A suitable clutch mechanism may be included in thecoupling between the shaft 22 and the conveyor 62, so that the conveyor62 is driven only when it is desired to unload the material in the tank56.

The illustrated apparatus also utilizes a vibratory feeder 79 which ismounted on posts 72 on the bed of the truck 10. The vibratory feeder 7%?includes a trough 74 which has an open top for receiving material, andwhich discharges the material from its left hand end in FIGURE 7. Theleft hand end of the trough 74 is coupled by a conduit 76 to the inlet,defined by the conduit 28, of the milling mechanism 16.

A hopper 80 is mounted on the upper end of the trough 74. As best shownin FIGURES 1, 4 and 7, this hopper has a rectangular configuration incross-section, and it has walls which slope inwardly from the top to thebottom.

The trough 74 maybe inclined slightly towards the conduit 76, and thetrough is driven by a suitable drive mechanism 86. The drive mechanism86 produces a vibratory rectilinear movement to the trough 74 in adirection to the left and right in FIGURE 7. The vibratory conveyor orfeeder 70 may be of the type manufactured and sold by the GeneralKinematics Corp. of Barrington, Illinois.

The classified material to be destroyed by the mechanism is deposited ina bin (FIGURE 8). This bin, and others like it, as described above, areplaced in different positions around the particular plant. Theclassified material to be ultimately destroyed is deposited in the binsthrough a slot 162. The slot 1R2, as shown in FIGURE 8, is formed in oneof two hinged covers 104 and 106.

The bin 109 is held locked by means of a bar 163 which extends through apair of brackets 110 and 1.12 and which is held in place by a padlock114. The padlock 114 may be a usual security approved padlock, and canbe unlocked only by a qualified security officer.

A pair of channels 115 and 118 are mounted on the bottom of the bin 1%,and these channels receive the forks 120 of a hydraulic lift 122. Thislift may have any usual and known construction, and it is mountedadjacent one side of the milling mechanism 16.

' The hydraulic lift 122 includes a pair of guides 124 which supportrespective movable chains. The movable chains are driven by controlledhydraulic means to move the forks 12% from a lower position shown inFIGURE 4 to an upper position shown in FIGURE 1. The guides 124 areshaped to have an upper arcuate configuration, so that the lift 122 iscapable of lifting the bin 108 from the position shown in FIGURES 3 and4 up to the position shown in FIGURE '1.

When the bin 1% is in the position shown in FIGURE 1, it is held in aninverted position over the top of the hopper 8G. The hopper 89 includesa notch 15% (FIG- URES l and 7) which receives the end of the lockingbar 108, so that the padlock 114 is positioned outside of the 75 hopper80. V

' The security officer may now unlock the padlock 114 and remove the bar103. When the bar 168 is removed, a spring-loaded plunger 152 on thehopper 8t enters into the bracket 11% of the bin 19, as shown in FIGURE7. This plunger may be locked in place by a padlock 154. The padlock 154may also be a security padlock, and it is locked in place by thesecurity otlicer after he unlocks the padlock 114 and removes the bar108. The locked plunger 152 serves to lock the bin in its invertedposition over the hopper 80.

When the bin is in its inverted position, and after the bar 168 has beenremoved, the cover members 104 and 1&6 open downwardly, as shown inFIGURE 7. This permits the material in the bin 16% to drop down into thetrough 74 of the vibratory feeder 70. It will be appreciated that thesystem is entirely closed and locked. That is, the bin 100 remainslocked by the padlock 114and locking bar 1118 until it is in positionover the top of the feeder 81 Then, the unlocking of the padlock 114 andremoval of the bar 168 permits the bin 100 to open into an enclosedhousing which is inaccessiblefrom the exterior. Also, the locking of thepadlock 154 causes the bin 1% to be securely locked on the hopper 80.

A glass covered inspection window 160 (FIGURE 7) may be provided in theside of the hopper 80 to enable the security oflicer to determineWhether or not the material in the mechanism has been in fact completelydestroyed. This inspection Window may be normally covered by a door 162(FIGURE 1), which is normally locked closed by a security padlock. Thedoor 1&2 may be opened only by a security ofiicer, to permit the desiredvisual inspection. Other similar windows may be provided at other partsof the apparatus, such as in the side of the actual milling mechanism 16itself.

As described above, in the practice of the invention, the mobile unit ofFIGURE 1 makes a scheduled stop at a particular plant. Prior to thisscheduled stop, a plurality of bins, such as the bin 1% of FIGURE 8, aregathered by a security ofiicer and brought to a designated area. Asnoted, this designated area may be just inside the main gate of theplant, and under the observation of the gate guard. The mobile unit thenenters the gate, and the bins 199 are successively lifted into positionso that their contents may be loaded into the apparatus.

As each bin is lifted into the position of FIGURE 1, the gate guardunlocks the padlock 114 and removes the locking bar 168. Then he looksthe padlock 154 to assure that the bin 1% is locked in place on top ofthe hopper 89. The mechanism is then started, and the material in thebin 1% is completely pulverized and fed to the tank 56. At thecompletion of the operation, the gate guard is signalled, and he makes avisual inspection through the windowlofi. I-Ie then unlocks the padlock.154, and the empty bin 1% is removed. The procedure in then repeatedfor each successive bin.

At the completion of the operation, the mobile unit It) may depart'forthe next plant. Whenever the tank 55 becomes full, it may be unloaded inthe described manner into any suitable conveyor, such as the vehicle 64.

The apparatus shown in FIGURES- 9 and 10 also utilizes many of thecomponents described above, and such components are not, for the mostpart, repeated in FIGURES 9 and 10. As will be described, the latterapparatus may be loaded in the manner described above in conjunctionwith the apparatus of FIGURES 1-8.

The apparatus shown in FIGURES 9 and 10 includes a pair of millingmechanisms 20!) and 2&2 which are,

mounted on top of one another, as shown in FIGURE 9. The millingmechanism 2% is relatively large and it may be designated asthe primarymill; whereas the milling mechanism 262 is relatively small, and it maybe designated as the secondary mill. These milling mechanisms may be ofthe above-described hammer mill type manufactured by the above-mentionedWilliams Com pany.

r The purpose of the provision of two milling mechanisms in'theapparatus of FIGURES 9 and 10 is to enable the apparatus to handlematerial of all shapes and sizes, and which normally would have atendency to plug the secondary mill. The primary mill 2G6 acts on theincoming material and reduces it to a size which can be convenientlyhandled by the secondary mill 202. The secondary mill then acts on thematerial from the primary mill and reduces it to the final desiredflutfy constituency.

The primary mill 200 includes a rotor 264 which is mounted on a controlshaft 206. The control shaft 206 is suitably journalled, and it isdriven by an appropriate drive engine, like the diesel engine 14 ofFIGURE 1.

The control shaft 206 serves to drive the rotor 2614 in a clockwisedirection insofar as the View of FIGURE 9 is concerned.

' A conduit 207 defines the inlet mouth to the primary milling mechanism200. An inspection door 209 may be mounted in the conduit 207. A grating268 is interposed between the outlet of the primary mill 2% and theinlet of the secondary mill 202, and this grating determines the size ofthe material to be fed from the primary mill into the secondary mill.

The secondary milling mechanism 202 includes a rotor 210 which ismounted on a drive shaft 212. The drive shaft 212 is driven, togethewith the drive shaft 296, from a suitable drive engine, such as thediesel engine 14 referred to above. The rotor 210 is also driven in aclockwise direction as seen in the view in FIGURE 9.

The outlet of the secondary miling mechanism 202 is coupled to an outletconduit 214 which, in turn, is coupled to a feed-line 216 (FIGURE 10). Ascreen 213 is positioned across the outlet of the secondary mill todetermine the constituency of the flufiy material fed to the outletconduit 214.

The'feed-line 216 extends to a separate unit 218 (FIG- URE- 10) which isin the form of a large housing mounted on a wheeled trailer, forexample, and which will be described in detail subsequently. In thepractice of the second embodiment of the invention, the mechanism ofFIGURE 9 and the drive engine are both mounted on a truck, such asshownin FIGURE 1, and the trailer of FIGURE 10 is coupled behind thetruck so as to provide mobility for the equipment.

The mechanism of FIGURES 9 and 10 also includes a fan 217 which isinterposed in the feed-line 21%, and which may be similar to the fandescribed above in conjunction with the previous embodiment. Thisfanserves to draw the-material through the primary and secondary mills260 and 292, and to discharge the resulting fluffy material through thefeed-line 216 into the housing 218. The fan 217 isdrivenby a separatemotor 219. This motor may, for example, be a four cylinder gasolineengine of about 42 horsepower. A clutch, not shown, may also be providedso as to control the flow of fiufi through the line 216. The motor 219drives the fan 217 'at, for example, 2109 r.p.m., and the mills aredriven at, for example, 1950 r.p.m., so as to assure ample flow of air.This separate and independent drive of the tan is advantageous in thatwhen the main diesel is caused to lose speed in the presence of largeloads dumped into the mechanism, the air flow through the mills does notdrop also but continues at a relatively high rate.

An open-ended chute, or hopper, 220 is mounted on top of the primarymilling mechanism 200 and over the inlet conduit 207 of that mechanism.Theupper end of the chute 220 has a pair of doors 224 and 226. Thesedoors are hinged to the sides of the chute and, when closed, extendacross the top of the chute to close the chute. The doors arehinged sothat they may open downwardly, as shown in FIGURE 9. a

The doors 224 and 226 are hydraulically controlled by suitable hydraulicmechanisms, such as the mechanism 228 shown in FIGURE 9. Each door maybe individually opened or closed by the actuation of its hydraulic.without clogging the entrance.

'5" mechanism. This actuation may be controlled, for example, by a pairof hand levers 239, 232' (FIGURE A bin, such as the bin 190, may beplaced, top down, over the top of the chute 220. This placement of thebin in position over the top of the chute 220 may be carried out by amechanism similar to the elevator mechanism illustrated in the previousembodiment and described in conjunction therewith.

However, in the apparatus of FIGURES 9 and 10, when the doors of the binare unlocked by the security ofiicer, they are not free to open, as inthe previous embodiment. Instead, the doors of the bin are held closedby the doors 224 and 226. The actuation of the doors 224 and 226provides a control for the feed of the material from the bin into theapparatus.

The apparatus of FIGURES 9 and 10 is advantageous in that it is capableof handling loads from the bins 10$ quickly and efiiciently, and withoutany likelihood of jamming the mills due to sudden excessive loads.Durthe operation of the apparatus, whenever the speed of the mills dropsbelow a particular threshold, thereby indicating an excessive load ofmaterial in the mills, the hand levers 230 or 232' can be operated toclose the doors 224 and 226 and thereby close the doors of the bins.This serves to reduce, or cut off, the loading of the apparatus untilthe work in process has been passed to the outlet, as indicated by therestoration of the normal speed of the mills.

As mentioned above, the provision of the large primary milling mechanism200 and of the smaller secondary milling mechanism 202 enables theapparatus shown in FIG- URES 9 and 10 to handle a Wide variety of loadsfrom the bin 2% without clogging or jamming. These loads may include,for example, thick books, stapled stacks of paper or blueprints, and soon. This flexibility in the handling capabilities of the latterembodiment are most desirable because security reasons prohibit theoperator from examining the contentsof any particular bin before suchcontents are fed into the apparatus.

The large area direct channel openings through the chute 22G directlyinto the mouth of the primary mill 200 assure that large pieces ofmaterial will be fed to the mill Then, and as mentioned above, theprimary mill grinds the material fed to it into smaller pieces which arefed to the secondary mill which, in turn, reduces them to the desiredfiutfy constituency.

The illustrated apparatus of FIGURES 9 and 10 is capable, therefore, ofhandling material of a large range of shapes and sizes. As mentioned,the primary milling mechanism 2% mills all the material down to a sizewhich will pass through the grating 208. This reduces the material tothe capabilities of the secondary mill 202. The

secondary mill then mills the pieces from the primary mill down to afluffy constituency which may be drawn by the fan down through thescreen 213 and into the conduit 214.

As mentioned, the flufiy material from the secondary mill 262 is thenblown through the feed-line216 into the interior of the housing 218. Asalso mentioned, the housing 218 is mounted on wheels 221, so as toconstitute a trailer which may be coupled onto the back of the trucksupporting the apparatus of FIGURE 9. A fragmentary.

portion 222 of the truck is shown, for example, in FIG- URE 10.

As illustrated, the housing 218 has a large rectangular V configuration.The flufiy material from the feed-line 216 is blown into the housingthrough aperture 225 in the roof of the housing. The fluffy material soblown into the housing has a tendency to drift back towardsthe rear. Theair stream passes through an outlet port 227 and through a pair offeed-lines 229 into a pair of porous collapsible filter dust bags 230.The dust bags 230 may be removed from time to time for cleaningpurposes. These dust bags serve to prevent fine dust from settlingaround the adjacent territory during the operation of the apparatus.

The trailer also includes a Water tank 232 which is mounted under thehousing 218. An associated pump 234 pumps water from the tank 232 upthrough an exterior water line 236 and into an interior sprinklingsystem 239. The interior sprinkling system causes water to be sprayed inthe interior of the housing 218 to settle the dust, and this serves toeliminate any danger of explosion.

A hydraulically operated blade 238 is mounted within the housing 21S,and it extends across the interior of the housing. The blade 238 ismovable from the left-hand end of the housing to the right-hand end byan appropriate hydraulic ram 240. The ram is operated by suitablecontrols.

From time to time during the operation of the apparatus, and after apredetermined number of loads, for example, the loading of the flufifymaterial into the housing 218 is discontinued fora time, and the blade238 is operated by the ram 240 to compress the fluffy material alreadyin the housing. During this operation, the blade 238 is moved by the ram24-43 from the left-hand end of the housing 218 to the right-hand end ofthe housing and the material is compressed against the back of thehousing. The blade is then returned to the left-hand end of the housing,and the next load of fiutiy material is blown into the housing. Thisoperation is continued until the housing 218 is filled with compressedfiufiy material.

A pair of hinged doors 242 are provided on the back of the housing 218.To unload the housing, it is merely necessary to open the doors 242, andthen to cause the .ram 240 to move the blade 238 towards the open backof the housing. This action causes the compressed material to bedischarged out the open back.

An inspection door 244 may be provided in the side of the housing. Thisinspection door is positioned, for example, towards the left-hand end ofthe housing.

The invention provides, therefore, an improved process for destroyingclassified material. As described above, the process of the inventionoperates on the basis of an entirely closed system, so that therequirement for security personnel is reduced to a minimum, and theentire operation may be supervised, for example, by a single securityoificer. Moreover, the presence of the security officer is not requiredcontinuously, but only when a new bin is to be fed into the mechanism.

While particular embodiments of the process of the invention have beenshown and described, modifications may be made. It is intended in thefollowing claims to cover all the modifications which fall within thespirit and scope of the invention.

What is claimed is:

1. A method of accumulating and destroying documents including:collecting the documents in locked receptacles at predeterminedlocations in a particular area; moving the filled receptacles to acommon documentdestroying station for discharge into adocument-destroying mechanism; and locking the receptacles to saiddocument-destroying mechanism during the discharge of the documents intosaid mechanism.

2. A method of accumulating and destroying docu ments including:collecting the documents in locked receptacles at predeterminedlocations in a particular area; moving the filled receptacles to acommon documentdestroying station for discharge into adocument-destroying mechanism; locking each receptacle to saiddocumentdestroying mechanism; and opening each receptacle as it is solocked to the mechanism so as to permit its contents to be dischargedinto the mechanism.

3. A method of accumulating and destroying documents including:collecting the documents in receptacles having locked doors thereon andpositioned at predetermined locations in a particular area; moving thefilled receptacles to a common document-destroying station for dischargeinto a document-destroying mechanism; inverting each receptacle over thedocument-destroying mechanism in a locked relationship with themechanism; and

unlocking the doors of the receptacle inverted over the mechanism topermit the contents thereof to be discharged into said mechanism.

4. A method of accumulating and destroying documents including:collecting the documents in receptacles having locked doors thereon andpositioned at predetermined 1ocations in a particular area; moving thefilled receptacles to a common document-destroying station for dischargeinto a document-destroying mechanism; inverting each receptacle over thedocument-destroying mechanism in a locked relationship with themechanism; unlocking the doors of each receptacle inverted over themechanism to permit the contents thereof to be discharged into themechanism; milling the documents discharged into the mechanism in aplurality of successive steps in the mechanism; pneumatically conveyingthe milled material from the mechanism to a press; and compressing themilled material in the press. a

5. The method defined in claim 4 and which includes the steps of liquidspraying thematerial in the press; and

collecting dust from the press in a separate filter means,

References Cited by the Examiner UNITED STATES PATENTS Erlinder et al214-302 WALTER A. SCHEEL, Primary Examiner.

BILLY I WILHITE, Examiner.

4. A METHOD OF ACCUMULATING AND DESTROYING DOCUMENTS INCLUDING:COLLECTING THE DOCUMENTS IN RECEPTACLES HAVING LOCKED DOORS THEREON ANDPOSITIONED AT PREDETERMINED LOCATIONS IN A PARTICULAR AREA; MOVING THEFILLED RECEPTACLES TO A COMMON DOCUMENT-DESTROYING STAATION FORDISCHARGE INTO A DOCUMENT-DESTROYING MECHANISM; INVERTING EACHRECEPTACLE OVER THE DOCUMENT -DESTROYING MECHANISM IN A LOCKEDRELATIONSHIP WITH THE MECHANISM; UNLOCKING THE DOORS OF EACH RECEPTACLEINVERTED OVER THE MECHANISM TO PERMIT THE CONTENTS THEREOF TO BEDISCHARGED INTO THE MECHANISM; MILLING THE DOCUMENTS DISCHARDED INTO THE